R-Fe-B sintered magnet
US10720271B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 25, 2017 |
| Grant date | Jul 21, 2020 |
| Priority date | — |
| Expiry date | Sep 12, 2038 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01F41/0293
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
An R—Fe—B base sintered magnet is provided comprising a main phase containing an HR rich phase of (R′, HR)2(Fe,(Co))14B wherein R′ is an element selected from yttrium and rare earth elements exclusive of Dy, Tb and Ho, and essentially contains Nd, and HR is an element selected from Dy, Tb and Ho, and a grain boundary phase containing a (R′, HR)—Fe(Co)-M1 phase in the form of an amorphous phase and/or nanocrystalline phase, the (R′, HR)—Fe(Co)-M1 phase consisting essentially of 25-35 at % of (R′, HR), 2-8 at % of M1 which is at least one element selected from Si, Al, Mn, Ni, Cu, Zn, Ga, Ge, Pd, Ag, Cd, In, Sn, Sb, Pt, Au, Hg, Pb, and Bi, up to 8 at % of Co, and the balance of Fe. The HR rich phase has a higher HR content than the HR content of the main phase at its center. The magnet produces a high coercivity despite a low content of Dy, Tb and Ho.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.